Bingxing Zhang

Proton exchange membrane water electrolyzers (PEMWEs) are central to renewable‐powered green hydrogen production. As the benchmark electrocatalyst for the oxygen evolution reaction (OER), conventional single‐phase IrO ₂ is constrained by linear scaling relations among oxygenated intermediates, compounded by severe mass‐transport limitations and poorly regulated interfacial water structures. Here, we design a Turing‐type MoO _x ‐IrO ₂ heterostructure with strongly coupled cluster‐scale interfaces, which enables dual‐function Ir‐Mo synergy that breaks fundamental kinetic limitations and optimizes interfacial water structures. At the reaction pathway level, Brønsted‐acidic MoO _x clusters promote water dissociation to generate reactive Mo─OH* intermediates, triggering radical coupling with adjacent Ir─O* species to form OOH* and thus circumventing the linear scaling relation. At the interfacial microenvironment level, MoO _x reorganizes the rigid hydrogen‐bonding networks and increases the population of free H ₂ O species, effectively alleviating concentration overpotentials under high‐current‐density operation. When integrated into a practical 25 cm ² membrane electrode assembly, this catalyst delivers a PEMWE cell voltage of 1.71 V at 3 A cm ⁻² and an ultralow degradation rate of ∼9.5 µV h ⁻¹ over 1000 h, with a total platinum‐group‐metal loading of merely 0.5 mg cm ⁻² across both electrodes. Our dual‐modulation strategy establishes a transformative paradigm for developing low‐iridium and durable OER electrocatalysts toward practical green hydrogen production.

Proton exchange membrane water electrolyzers (PEMWEs) are central to renewable‐powered green hydrogen production. As the benchmark electrocatalyst for the oxygen evolution reaction (OER), conventional single‐phase IrO ₂ is constrained by linear scaling relations among oxygenated intermediates, compounded by severe mass‐transport limitations and poorly regulated interfacial water structures. Here, we design a Turing‐type MoO _x ‐IrO ₂ heterostructure with strongly coupled cluster‐scale interfaces, which enables dual‐function Ir‐Mo synergy that breaks fundamental kinetic limitations and optimizes interfacial water structures. At the reaction pathway level, Brønsted‐acidic MoO _x clusters promote water dissociation to generate reactive Mo─OH* intermediates, triggering radical coupling with adjacent Ir─O* species to form OOH* and thus circumventing the linear scaling relation. At the interfacial microenvironment level, MoO _x reorganizes the rigid hydrogen‐bonding networks and increases the population of free H ₂ O species, effectively alleviating concentration overpotentials under high‐current‐density operation. When integrated into a practical 25 cm ² membrane electrode assembly, this catalyst delivers a PEMWE cell voltage of 1.71 V at 3 A cm ⁻² and an ultralow degradation rate of ∼9.5 µV h ⁻¹ over 1000 h, with a total platinum‐group‐metal loading of merely 0.5 mg cm ⁻² across both electrodes. Our dual‐modulation strategy establishes a transformative paradigm for developing low‐iridium and durable OER electrocatalysts toward practical green hydrogen production.

Electrochemical CO2 reduction reaction (CO2RR) provides an attractive route for converting CO2 into value-added fuels and chemicals using renewable electricity. However, its practical development is still hindered by thermodynamic stability and kinetic inertness of CO2, the competing hydrogen evolution reaction, and the complex multielectron–proton reaction pathways. Atomically precise metal nanoclusters (NCs) have emerged as a distinctive class of CO2RR electrocatalysts owing to their well-defined compositions, discrete electronic structures, abundant low-coordination metal sites, and highly tunable surface microenvironments. In this review, we summarize recent advances in ligand-protected and supported metal NCs for CO2 electroreduction with emphasis on reaction mechanisms and structure–performance relationships. We first discuss reaction mechanisms obtained from atomically precise NCs as model systems for identifying active sites, key intermediates, and selectivity-determining steps. Then, ligand engineering for regulating the catalytic performance of NCs is highlighted, including conventional ligand protection, functional ligand engineering, and controlled ligand removal or reconstruction, which regulate electronic structures, cation accumulation, interfacial solvation, and local reaction environments. Subsequently, supported metal NCs are discussed by classifying support effects into conductive or defective carbon interfaces, heteroatom-doped carbon, and metal oxide/zeolite-based confined interfaces. Finally, we outline current challenges and future opportunities in precise synthesis, operando characterization, theoretical modeling, dynamic structural stability, and device-level evaluation, aiming to guide the rational design of next-generation nanocluster electrocatalysts for CO2RR and beyond.

Urea is an indispensable nitrogen fertilizer and an important feedstock for chemical synthesis. Compared to the energy-intensive Bosch–Meiser process, photocatalytic redox coupling offers a sustainable approach toward urea synthesis. However, artificial photosynthesis remains dependent on catalyst compositions and structural properties. Here, by leveraging the photocatalyst-like redox capability of aqueous microdroplets, we present a catalyst-free, radical-mediated redox coupling strategy for urea synthesis from CH3OH and N2 under ambient conditions. The system achieved an optimized urea yield rate of approximately 10.8 μg h–1 with 2 vol % CH3OH in a pure N2 atmosphere, which was comparable to some values for urea photosynthesis. Comprehensive experimental investigations and theoretical calculations elucidated a thermodynamically favorable redox coupling pathway, in which ·CHO generated from ·OH-induced CH3OH oxidation and ·NH2 produced via ·H-triggered N2 reduction played a pivotal role in urea formation. This study offers a promising platform for the green synthesis of organonitrogen compounds and provides insights into harnessing the redox chemistry of aqueous microdroplets for chemical production.

Artificial N ₂ reduction offers a sustainable approach to green NH ₃ synthesis, but the practical implementation is challenged by N ₂ activation and competing hydrogen evolution. Photoelectrochemical nitrate and nitrite (NO _x ^– , x = 2 and 3) reduction with favorable thermodynamics represents a promising alternative for NH ₃ production, provided that NO _x ^– can be supplied from the atmosphere. Here, through leveraging water microdroplet chemistry and dynamic photoelectrode–electrolyte interface engineering, we report a tandem air–NO _x ^– –NH ₃ conversion system that integrates catalyst-free N ₂ oxidation with pulsed photoelectrochemical NO _x ⁻ reduction (mNOR-pPNO _x R). The system achieves efficient and selective NH ₃ production with a yield rate of 24.5 μmol cm ⁻² h ⁻¹ at −0.2 V _RHE , which are two to three orders of magnitude higher than conventional photo/electrocatalytic N ₂ fixation. This study introduces insights for decentralized, on-demand ammonia production from air and water and broadens horizons of microdroplet chemistry and pulse strategy for sustainable chemical manufacturing.

The quest for efficient solar‐driven water splitting, a promising avenue for clean fuel production, faces challenges due to limited solar energy conversion efficiency. Traditional approaches study the overall water splitting as two spatially separate half reactions on two unrelated sites, hindering full utilization of photogenerated charge and water molecules. To overcome these limitations, an integrated cluster heterostructure catalyst on InGaN/GaN semiconductor nanowires is proposed for the effective utilization of photogenerated charge carriers and water molecules on the same redox localization. By establishing the fast charge extraction kinetics based on InGaN/GaN nanowires, the integration of Rh and MoRhO _x clusters on the nanowire surface enables simultaneous and fast hydrogen/oxygen evolution reactions at the cluster heterostructure. Furthermore, the integrated strategy can enhance the charge redistribution across the heterostructure between the two clusters, further optimizing adsorption of reaction intermediates on each cluster for boosted photocatalytic water splitting activity. Consequently, the integrated heterostructure triggers a 40‐fold increased hydrogen production efficiency in an artificial leaf system. This study provides valuable insights for the rational design of advanced heterostructured photocatalysts for water splitting and beyond.

The quest for efficient solar‐driven water splitting, a promising avenue for clean fuel production, faces challenges due to limited solar energy conversion efficiency. Traditional approaches study the overall water splitting as two spatially separate half reactions on two unrelated sites, hindering full utilization of photogenerated charge and water molecules. To overcome these limitations, an integrated cluster heterostructure catalyst on InGaN/GaN semiconductor nanowires is proposed for the effective utilization of photogenerated charge carriers and water molecules on the same redox localization. By establishing the fast charge extraction kinetics based on InGaN/GaN nanowires, the integration of Rh and MoRhO _x clusters on the nanowire surface enables simultaneous and fast hydrogen/oxygen evolution reactions at the cluster heterostructure. Furthermore, the integrated strategy can enhance the charge redistribution across the heterostructure between the two clusters, further optimizing adsorption of reaction intermediates on each cluster for boosted photocatalytic water splitting activity. Consequently, the integrated heterostructure triggers a 40‐fold increased hydrogen production efficiency in an artificial leaf system. This study provides valuable insights for the rational design of advanced heterostructured photocatalysts for water splitting and beyond.